well a 911 motor is worth good money, that would be the first year of the 2.7L at the very least a couple grand, and everything in that car is worth money, not just guages, you could part out that car, no matter what kind of 911 it is on Ebay for good money.
on the other hand if its a 914 targa, then its not really worth drooling over unless its a smoking deal.
its hard to say prices because we would need to see pictures of what shape the cars are in, has it been sitting for years, how many miles on the motor ect.